The electrochemical element, particularly the lithium ion battery, which is compact and light, having high energy density, and capable of repeating the charge and discharge has rapidly increased the demand by utilizing its characteristics. Also, the electrochemical element which is represented by the lithium ion secondary battery is expected to be used for a small scale purpose such as for the mobile phone or a laptop computer to a large scale purpose such as for in-vehicle, as it has large output density and energy density. Therefore, for these electrochemical element, along with the increase and development of the use of purpose, further improvements is demanded for lower resistance, higher capacity, high voltage resistance, mechanical characteristic, and cycle lifetime or so.
The electrochemical element increases the operating voltage by using the organic electrolytic solution, thereby the energy density can be increased, however on the other hand, since the viscosity of the electrolytic solution is high, there was a problem that the inner resistance was large.
In order to reduce the inner resistance, it is proposed to provide the conductive adhesive layer in between the electrode composition layer and the collector (Patent document 1). The conductive adhesive agent of the patent document 1 includes the carbon black as the conductive material, and includes the polyvinylidenefluoride resin as the binder.
Patent document 2 teaches to provide, in the electrode for the lithium ion capacitor, the conductive adhesive layer in between the collector and the electrode composition layer in order to improve the electrode strength and to reduce the inner resistance. Also, Patent document 2 describes polyamide or acrylate polymer or so as examples of the binder used for the conductive adhesive agent. Also, it describes that acrylate polymer may include a dibasic acid monomer such as fumaric acid, itaconic acid or so.